M3 submachine gun
The M3 is an American .45-caliber submachine gun adopted by the U.S. Army on 12 December 1942, as the United States Submachine Gun, Cal. .45, M3. The M3 was chambered for the same .45 ACP round fired by the Thompson submachine gun, but was cheaper to mass produce and lighter, at the expense of accuracy. The M3 was commonly referred to as the "Grease Gun" or simply "the Greaser," owing to its visual similarity to the mechanic's tool.
| Submachine Gun, Cal. .45, M3 | |
|---|---|
World War II–era Guide Lamp M3 submachine gun with 30-round magazine and other accessories. The Buffalo Arms bolt in this original M3 is dated January 1944. | |
| Type | Submachine gun |
| Place of origin | United States |
| Service history | |
| In service | 1943–present |
| Used by | See Users |
| Wars |
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| Production history | |
| Designer | George Hyde |
| Designed | 1942 |
| Manufacturer | General Motors, others |
| Unit cost | Approx. US$15 (1943; equivalent to $254 in 2022) |
| Produced | 1943–1945 early 1950s |
| No. built | Total: 655,363
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| Variants |
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| Specifications | |
| Mass |
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| Length | 29.1 in (740 mm) stock extended / 21.9 in (556.3 mm) stock collapsed |
| Barrel length | 8 in (203.2 mm) |
| Cartridge |
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| Action | Blowback, open bolt |
| Rate of fire | 450 rounds/min cyclic (= 7½ / second) |
| Muzzle velocity | 900 ft/s (274 m/s) |
| Effective firing range | Sights fixed to 100 yards (91 m) |
| Feed system | 30-round detachable box or 32-round detachable box magazine |
| Sights | Fixed rear peep sight and blade foresight, calibrated to 100 yards for caliber .45 M1911 ball ammunition |
The M3 was intended as a replacement for the Thompson, and began to enter frontline service in mid-1944. The M3A1 variant was used in the Korean War and later conflicts.
The M14 rifle, adopted in 1959, was intended to replace the M3A1 (as well as the M1 Garand, M1918 Browning Automatic Rifle and the M1 carbine) but the recoil of the M14's 7.62×51mm NATO cartridge proved too powerful for the submachine gun role. The M14 was in turn replaced by the M16 rifle in 1964, and this weapon (firing the intermediate 5.56×45mm NATO cartridge) was a better replacement for the M3A1. M3A1 submachine guns were retired from U.S. frontline service after 1959, but continued to be issued, for example as backup weapons for armored vehicle crews as late as the Gulf War (1990-1991). Many overseas US military bases continued to issue these for certain crews into the mid to late 1990s.